feat: migrate frontend to Astro SSG with design system

- Replace monolithic React SPA (App.tsx) with 7 Astro pages (+ routing)
- Implement full design system from design/ (OKLCH tokens, Tailwind 4 @theme)
- Add 12 Astro components (Button, Badge, Card, Sidebar, Header, states)
- Add 11 React islands (AuthGuard, MessageFeed, VoiceControls, AudioVisualizer, etc.)
- Add 3 Zustand stores (UI, voice, message state)
- Add CSS architecture: dark/light themes, glassmorphism, fluid typography, animations
- Add 404, login, settings, recordings pages
- Remove 40+ legacy React SPA files
- Add Particles background and MascotChat deferred islands
- Wire WebSocket bridge for real-time messages and voice events

Build: 7 pages in ~900ms
Typecheck: clean (0 errors)
Lint: clean (0 errors)

services/frontend/astro.config.mjs

@@ -36,10 +36,8 @@ export default defineConfig({
         "imphnen.asepharyana.web.id",
       ],
       watch: {
-        // Penting: Astro punya public/ dir sendiri, jangan bentrok
         ignored: ["!**/node_modules/**"],
       },
     },
-    // PostCSS otomatis terdeteksi dari root project
   },
 });